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Biology and Skin Color
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BIOLOGY AND SKIN COLOR
Sened Teklay, AP Biology Class 3
Colors of Humanity
When you look at these beautiful babies, what is the first thing you notice or perhaps grabs your attention?
The Skin color perhaps?
When viewing a human being, many colors are projected from different sources. Whether it be skin color, eye color, or hair color. However what grabs people's attention most is the skin color.
It is part of our identity! BUT DOES NOT DEFINE WHO WE ARE AS A PERSON.
Our skin color is one of the most precious traits we human beings have. Having a certain skin tone, can allow us or people around us predict our ancestry or where we came from.
Beautiful Melanin!
Topic
Melanin is the pigment that gives our hair , eyes , and skin the color it has.
- melanin is provided from skin cells called Melanocytes.
The more the melanin the darker the skin.
Melanin in SKIN!
Melanin is the pigment released by skin cells known as Melanocytes after exposure to sunlight. Melanin is stored in sacs called melanosomes. The more melanosomes present, the more the UV rays would be scattered.
- The more sunlight exposure, the more melanin, the darker the skin.
Eumelanin
Type of melanin responsible for dark (brown) pigmentation of skin.
There are two types:
- Black eumelanin
- Brown eumelanin
Pheomelanin
Type of melanin responsible for red/pink pigmentation of skin.
Melanin and Evolution
Topic
Human skin color has evolved to adapt to the climate change and exposure of UV (ultra-violent) rays of different places.
- rapid changes in nature demanded quick adaptations.
NATURAL SELECTION
Africa around the equator!
Africa has experienced tremendous climate changes and faces very high exposure to sunlight. Blood vessel on naked skin surfaces were easily getting destroyed therefore dark skin began to evolve.
Melanin as a defense mechanism?
Topic
Human skin is continuously exposed to environmental conditions that may potentially cause damage to our cells. There fore we need certain mechanisms in order to adapt to these external factors. UV Rays from the sun is one of the them
. UV rays from the sun may damage our skin cells (melanocytes) leading up to skin cancer. how does melanin play a role in this?
The Role of Melanin
People with darker skin have much lower chances of getting sun burnt due to increased melanin levels
Melanin will be released from small pigment sacs called melanosomes and will absorb the UV rays from the sun and distribute it. (instead of the UV rays being concentrated one one part).
Melanoyctes will use the release of melanosomes as a combating mechanism in order to fight off the occurrence of skin cancer.
Melanin is capable of dissipating UV rays as heat.
Absorption Spectrum
When UV Radiation approach the skin, melanin absorbs the solar energy and its electrons get into their excited states.
Topic
Vitiligo
Topic
Skin loses its pigment cells, due to the destruction of melanocytes.
- Patchy loss of color.
In vitiligo there are not much melanin to give your skin a color, therefore the skin starts losing its color.
- Loss of color in many tissues such as parts surrounding the mouth, arms, legs, eyes nose.